Chapter 13.08


Article I. General Provisions

13.08.010    Authority.

13.08.020    Purpose and objectives.

13.08.030    Administration.

13.08.040    Definitions.

13.08.050    Applicability.

13.08.060    Connection to public sewer system – Required when.

Article II. Permit

13.08.070    Required – Nontransferability – Authority.

13.08.080    Application – Fee.

13.08.090    Review.

13.08.100    Inspection – Fee refund.

13.08.110    Double fees for illegal system installation.

13.08.120    Permit – Construction plan.

13.08.130    Flood control zone permit required.

13.08.140    Strict adherence requirements.

Article III. Design

13.08.150    Subdivision and individual site review.

13.08.160    Determination of site characteristics.

13.08.170    Minimum land area requirement.

13.08.180    Location and setbacks.

13.08.190    Construction.

Article IV. Inspection

13.08.200    Authority – Approval – Recordation.

13.08.210    Extra-trip fee.

13.08.220    Illegal system installation.

13.08.230    Advance notice.

13.08.240    Sand filter or mound systems.

Article V. Alternative Systems

13.08.250    Establishment of guidelines.

13.08.260    Evaluation of guidelines.

13.08.270    Sand approval.

13.08.280    Pumps and siphons – Conditions.

13.08.290    Common point design flows.

13.08.300    Pressurized distribution systems.

13.08.310    Monitoring.

13.08.320    Graywater treatment.

13.08.330    Pit privies.

Article VI. Experimental Systems

13.08.340    Approval.

13.08.350    Use.

13.08.360    Guidelines.

13.08.370    Performance monitoring.

Article VII. Larger On-Site Systems

13.08.380    Review and approval.

Article VIII. Installer Requirements

13.08.390    Installation by certified installer required.

13.08.400    Certification requirements.

13.08.410    Resident owner doing work.

Article IX. Pumper Requirements

13.08.420    Permit required.

13.08.430    Permit and renewal – Application.

13.08.440    Pump tank requirements.

13.08.450    Waste removal and disposal.

Article X. Alternative System
Designer Program

13.08.460    Designer’s license.

13.08.470    Examination.

13.08.480    License fee.

13.08.490    Surety bond.

13.08.500    Suspension of designer’s license.

13.08.510    Revocation of sewage system designer’s license.

Article XI. Appeals

13.08.520    Appeal of health officer decision.

Article XII. Waiver

13.08.530    Waiver.

Article XIII. Compliance

13.08.540    Human occupancy.

13.08.550    No surface discharge.

13.08.560    Malfunctioning system – Vacation of premises.

13.08.570    Violation – Abatement.

13.08.580    Injunction.

13.08.590    Condemnation.

13.08.600    Violation – Penalty.

Article I. General Provisions

13.08.010 Authority.

Pursuant to the authority of RCW 43.20.050 (Powers and Duties of State Board of Health), these regulations are established as minimum requirements of the county board of health, governing on-site sewage systems. (Statutory Authority: RCW 43.20.050, 83-1). (Order 259, p. 248-96-010, filed 6/3/83: Order 101, p. 248-96-010, filed 6/10/74.) (Ord. 85-1 § 1, 1985).

13.08.020 Purpose and objectives.

A. The purpose of the regulations set out in this chapter is to assure protection of public health by minimizing:

1. Public health effects of on-site sewage systems on surface and groundwater,

2. Potential for public exposure to sewage;

B. Establish design, installation, and management requirements for on-site sewage system to accommodate long-term treatment and disposal of sewage. (Ord. 85-1 § 2, 1985).

13.08.030 Administration.

The health officer and local board of health shall administer these regulations under the authority and requirements of Chapters 70.06, 70.46, and 43.20 RCW. As provided in RCW 70.05.060(7), fees may be charged for this administration. (Ord. 85-1 § 3, 1985).

13.08.040 Definitions.

A. “Alternative system” means any on-site sewage system consisting of treatment and/or disposal components other than a septic tank and subsurface soil absorption system (SSAS).

B. “Approved” means acceptable by the health officer as stated in writing.

C. “Board of health” means the county board of health as defined in Chapters 70.07, 70.08, and 70.46 RCW.

D. “Cover” means soil material that is used to cover a subsurface disposal area.

E. “Cuts and/or banks” means any naturally occurring or man-formed slope which is greater than 100 percent (45 degrees) and extends vertically at least five feet from the toe of the slope to the top of the slope as follows:

F. “Drain rock” means crushed stone, gravel, slag, or other noncompatible material of equivalent strength and durability, from three-fourths-inch to three-inches in diameter and free from fine particles such as dust, sand, silt, or clay.

G. “DSHS” means the Washington State Department of Social and Health Services.

H. “Experimental system” means any alternative on-site system excluding a larger system which has not yet had guidelines established by the technical review committee as per WAC 248-96-046.

I. “Gross land area” means lot area which is bounded by the centerline of adjoining road or street right-of-ways within the boundaries of the proposed development.

J. “Groundwater” means subsurface water occupying the zone of saturation, permanently or seasonally (the top surface of which is commonly referred to as the water table), indication of which may be demonstrated by one or all of the following methods:

1. Water seeping into or standing in an open excavation from the soil surface surrounding the excavation;

2. Spots or blotches of different color or shades of color interspersed with a dominant color in soil, commonly referred to as mottling. This is caused by intermittent periods of saturation and drying, and may be indicative of poor aeration and impeded drainage.

K. “Health officer” means the health officer of the city, county, or city-county health department or district or a representative authorized by and under the direct supervision of the health officer.

L. “Larger on-site sewage system” means any on-site sewage system with design flows, at a common joint, between 3,500 and 14,500 gallons per day. On-site sewage systems receiving state or federal grants, or systems using mechanical treatment or lagoon with ultimate design flows above 3,500 gallons per day are excluded from this definition. Excluded systems are governed by Chapter 173-240 WAC which is administered by the Washington State Department of Ecology.

M. “Mound” means an alternative system meeting the design criteria for fill and mound systems developed by the technical review committee in which sewage effluent is distributed by low pressure over a suitable fill material laid on properly prepared original soil.

N. “On-site sewage system” means any system of piping, treatment devices or other facilities that convey, store, treat, or dispose of sewage on the property where it originates or on adjacent or nearby property under the control of the user where the system is connected to a public sewer system.

O. “Ordinary high-water mark” means the mark on all lakes, streams and tidal waters, which will be found by examining the beds and banks and ascertaining where the presence and action of waters are so common and usual, and so long continued in all ordinary years, as to mark upon the soil a character district from that of abutting upland, in respect to vegetation, as that condition exists on the effective date of the ordinance codified in this chapter, or as it may naturally change thereafter; provided, that in any area where the ordinary high-water mark cannot be found, the ordinary high-water mark adjoining saltwater shall be the line of mean high water.

P. “Percolation test” means a soil test performed at the depth of the bottom of a proposed subsurface soil absorption system to estimate the water absorption capability of the soil. The results are normally expressed as the rate in minutes at which one inch of water is absorbed.

Q. “Person” means an individual, corporation, company, association, society, firm, partnership, joint stock company, or any branch of state or local government.

R. “Public sewer system” means a sewerage system which is owned or operated by a city, town, municipal corporation, county, political subdivision of the state, or other approved ownership consisting of a collection system and necessary trunks, pumping facilities and a means of final treatment and disposal and approved or under permit from the Department of Ecology.

S. “Restrictive layer” means a layer that impedes the movement of water, air, and growth of plant roots. Examples of such layers or conditions are groundwater tables, hardpans, claypans, fragipans, compacted soil, bedrock, and clayey soil.

T. “Sand filter” means an alternative system meeting the design criteria for sand filters developed by the technical review committee in which sewage is distributed by low pressure distribution over medium sand collected and then disposed of through a subsurface absorption system.

U. “Septic tank” means a watertight pretreatment receptacle which receives the discharge sewage from a building sewer or sewers, and is designed and constructed so as to permit separation of settleable and floating solids from the liquid detention and digestion of the organic matter, prior to discharge of the liquid portion.

V. “Sewage” means the water-carried human or domestic waste from residences, buildings, industrial establishments, or other facilities, together with such groundwater infiltration that may be present.

W. “Soil log” means an excavation in soil of sufficient size and depth made to allow adequate determinations of the soil’s characteristics together with the detailed description of the soil’s texture, color, bulk density or compaction, water absorption capabilities or permeability, and/or any other characteristics providing information as to the soil’s capacity to act as an acceptable treatment and disposal medium for sewage.

X. “Subdivision” means a division of land, as defined in Chapter 58.17 RCW, now or hereafter amended, including both long and short subdivisions.

Y. “SSAS” means subsurface soil absorption system. A system consisting of trenches (three feet or less in width) or beds (more than three feet in width), together with the piping and gravel, designated and installed in original undisturbed soil for the purpose of receiving effluent from a septic tank or other pretreatment device and transmitting it into soil.

Z. “Surface water” means any body of water, whether fresh or marine, which either flows or is contained in natural or artificial depressions for significant periods of the year. Such bodies include, but are not limited to, natural and artificial lakes, ponds, rivers, streams, swamps, marshes and tidal waters.

AA. “Technical review committee” means a committee established and maintained by DSHS to review and evaluate alternative systems and establish guidelines for use. The committee is composed of a maximum of seven members acting as qualified representatives from various regulatory and development concerns.

BB. “Type 1 soil” means soil with USDA Soil Conservation Service textural classification coarser than a medium sand where the treatment potential is determined by the health officer or DSHS to be ineffective in retaining and/or removing substances of public health significance to underground sources of drinking water. Soils of other textural classifications may also be considered Type 1 where the treatment potential is determined by the health officer or DSHS to be ineffective in retaining and/or removing substances of public health significance to underground sources of drinking water.

CC. “Vertical separation” means the depth of unsaturated soil that exists between the bottom of SSAS and a restrictive layer. (Ord. 85-1 § 4, 1985).

13.08.050 Applicability.

A. These regulations shall apply to all on-site sewage systems except the following:

1. New construction for which a permit was issued prior to adoption of the ordinance codified in this chapter and is still valid. The regulations in effect at the time the permit was issued shall apply, except where portions of this chapter are less stringent;

2. An extension, alteration or replacement necessitated by the failure of an existing on-site sewage system. The regulations set out in this chapter shall be applied to the maximum extent permitted by the site. A permit shall be required as per Article II, (Permit);

3. Facilities constructed or operated in accordance with a permit or approval issued by the Washington State Department of Ecology. Where these regulations may be in conflict with Chapters 90.48 or 70.95 RCW, said RCW shall govern.

B. Any existing SSAS which was not installed under a permit issued by the county health department and whose use has been discontinued for a period of at least three years, because the residential or commercial structure it had been serving has been vacated or destroyed, shall remain unused or be brought in to full compliance with all applicable state and local regulations before its use is resumed. If the SSAS cannot be brought into full compliance with all applicable regulations and cannot be replaced with an SSAS or alternative system meeting all applicable regulations and guidelines, the health officer shall consider the parcel nonhabitable. (Ord. 85-1 § 5, 1985).

13.08.060 Connection to public sewer system – Required when.

A. Connection of any existing dwelling unit or other premises with a failing on-site sewage system shall be made to a public sewer system where there is adequate public sewer within 200 feet of the dwelling or other facility to be served as measured along the usual or most feasible route of access, and such connection is permitted by the sewer utility. This requirement may be waived if the health officer determines that adequate site conditions exist which allow the installation of a replacement on-site sewage system.

B. New construction within 200 feet of a public sewer system shall be connected if such connection is permitted by the sewer facility. (Ord. 85-1 § 6, 1985).

Article II. Permit

13.08.070 Required – Nontransferability – Authority.

No person shall install a new sewage disposal system nor perform major alterations, extensions, or relocations on an existing system without a valid permit issued by the health officer. Permits for alterations or repairs shall be so identified. Applications for such permits shall be made in writing in a manner prescribed by the health officer. The permit is not transferable. The authority to issue permits shall not be delegated by the health officer except in the case of larger on-site systems which are reviewed and approved by DSHS. (Ord. 85-1 § 7(A), 1985).

13.08.080 Application – Fee.

All persons proposing to install, renovate, or alter a new or existing sewage disposal system shall apply at the permit counter for a sewage permit. A fee established by current, adopted schedule shall be paid with such application. (Ord. 85-1 § 7(B), 1985).

13.08.090 Review.

A special permit for all alternative sewage systems must be obtained prior to any construction. Upon receipt of the application and required fee, plans will be reviewed by the health officer. (Ord. 85-1 § 7(C), 1985).

13.08.100 Inspection – Fee refund.

The health officer shall make inspection of the site prior to any construction, examine the soil conditions, natural features of the site, and set requirements concerning the design, location, and installation of a proper sewage disposal system. In the event that the health officer determines a site is unsuitable for the installation of a given type of sewage disposal system, it shall be so indicated in writing with the reasons for such determination. One-half of the application fee will be refunded if the site is determined to be unsatisfactory for on-site sewage disposal. (Ord. 85-1 § 7(D), 1985).

13.08.110 Double fees for illegal system installation.

Double fees shall be charged for illegally installed systems. (Ord. 85-1 § 7(E), 1985).

13.08.120 Permit – Construction plan.

When applying for a permit to install an on-site sewage system, a construction plan shall contain information as required by the health officer in sufficient detail and to a scale which will permit a proper evaluation of the application. A period of five working days may be required to complete the necessary field work and process a septic tank application. Additional time may be required if more soils information is necessary, or weather does not permit. Such information shall contain the following as a minimum:

A. Name of applicant and legal parcel number as obtained from the county assessor’s office;

B. Soil evaluation as required by the health officer;

C. Percolation test data where required or if obtained;

D. Maximum seasonal groundwater table;

E. General topography of the site and site drainage characteristics;

F. Distances of proposed system to existing water or planned systems, banks or cuts, property boundaries, structures or other improvements, surface water, or rock outcroppings;

G. Distance to public sewer system;

H. Source to potable water supply;

I. Known encumbrances affecting system placement and/or operation;

J. Percent and direction of slope;

K. Lot size. (Ord. 85-1 § 7(F), 1985).

13.08.130 Flood control zone permit required.

For any on-site sewage system proposed to serve a structure requiring a flood control zone permit under provisions of Chapter 86.16 RCW and Chapter 508-60 WAC, the installation permit shall not be issued until a flood control zone permit has been issued. (Ord. 85-1 § 7(G), 1985).

13.08.140 Strict adherence requirements.

Any on-site sewage disposal permit shall be considered null and void when the system installed is not in strict adherence to the design, depth and location approved by the health officer when issuing the permit. (Ord. 85-1 § 7(H), 1985).

Article III. Design

13.08.150 Subdivision and individual site review.

A. Subdivisions. Preliminary tests for subdivisions utilizing individual on-site sewage systems shall include at least one representative soil log per acre or tract or more as required by the health officer. A reduced number of soil logs may be allowed if adequate soils information is available.

B. Individual Sites. At least one soil log shall be performed at the site of each disposal area. This requirement may be waived by the health officer if adequate soils information is available. Additional soil logs may be required when the soil characteristics vary.

C. Individuals performing subdivision and individual site reviews shall meet the requirements and use the procedures specified in OCC 13.08.160(B). (Ord. 85-1 § 8(A), 1985).

13.08.160 Determination of site characteristics.

A. Site characteristics shall be determined in accordance with Chapter 3 and Appendix A of “Design Manual: On-site Wastewater Treatment and Disposal Systems,” United States Environmental Protection Agency, Report No. EPA-625/1-80-012, October, 1980, except where modified or in conflict with the regulations set out in this chapter.

B. The textural classification of a soil shall be determined by using normal laboratory and/or field procedures such as particle size analyses and percolation tests. Following are the specific soil textural classifications and soil type designations. The soil textures in Table 7-2 of the design manual referenced in subsection A of this section are amended as follows:

Soil Type

Soil Textural Classifications1


Course sands or coarser


Medium sand


Fine sand, loamy sand


Sandy loam, loam


Porous, well-developed

structure in silt and silt loams


Other silt loams, silty clay

loams, and clay loams.

1According to the United States Department of Agriculture, Soil Conservation Service’s soil classification system.

2Includes other soils and/or conditions where the treatment potential is ineffective in retaining and/or removing substances of public health significance to underground sources of drinking water.

C. All site evaluations shall be performed by or under the direct supervision of the health officer, a registered sanitarian, professional engineer, registered soil scientist (American Registry or Certified Professionals in Agronomy, Crops and Soils), or certified designer having knowledge and experience in the areas of soil and wastewater treatment and disposal.

D. All soil tests shall be conducted using uniform procedures and terminology as set forth in Chapter 3 and Appendix A of the manual referred to in OCC 13.08.190(A);

E. If sufficient information is not available concerning water table conditions, the health officer or department may require that the soils analysis be performed during the months of suspected highwater table conditions. (Ord. 85-1 § 8(B), 1985).

13.08.170 Minimum land area requirement.

A. A minimum lot size of three acres shall be required on new long subdivisions when there is no public water supply.

B. Minimum land area requirements for any development located outside the planning area described in subsection C of this section shall be determined for each single-family residence or each unit volume of sewage (450 gallons per day) by one of the following methods:

1. Method I. The following table notes the minimum land area required per unit volume or single-family residence based upon soil type and the type of water supply:

Minimum Land Area Required Per Unit
Volume of Sewage or Single-Family Residence

*Soil Type

Type of Water
















1 acre

12,500 sq. ft.

15,000 sq. ft.

18,000 sq. ft.

20,000 sq. ft.

22,000 sq. ft.


Each Lot

2 acres

1 acre

1 acre

1 acre

2 acres

2 acres

*Soil types are defined in OCC 13.08.160 (Determination of site characteristics).

**Except for long subdivisions where a minimum lot size of three acres shall be required.

2. Method II.

a. On-site sewage systems shall be installed on lots, parcels or tracts that have a sufficient amount of area with proper soils in which sewage can be retained and treated properly on-site. Justification demonstrating the development has sufficient area with proper soils to adequately retain and treat sewage on-site shall be provided in a report. The report shall fully support the conclusions reached by the proper analysis of all needed data. All such data shall be contained or referenced. This justification shall be contained or referenced. This justification shall be sufficient to enable the health officer to establish minimum gross land area requirements. The gross land area requirements for each unit volume of sewage or for each single-family residence shall be 12,500 sq. ft. Application of this will result in a maximum single-family residence density of 3.5 units per acre or for other development a maximum flow density of 1,570 gallons of sewage per acre per day. Factors that must be considered in the report shall include but not be limited to the following:

i. Soil type and depth;

ii. Area drainage, development and/or lot drainage;

iii. Public health impact on groundwater and surface water quality;

iv. Setbacks from property lines, water supplies, etc.;

v. Source of domestic water;

vi. Topography, geology, and groundcover;

vii. Climatic conditions;

viii. Availability to public sewers;

ix. Activity or land use, present, and anticipated;

x. Growth patterns;

xi. Reserve areas for additional subsurface disposal;

xii. Anticipated sewage volume;

xiii. Compliance with zoning and other requirements;

xiv. Possible use of alternative systems or designs;

xv. Other justification submitted by the developer.

b. If the report in subsection B(2)(a) of this section identifies Type 1 soils, the health officer may allow a reduction below the requirements noted in the table in subsection B(2)(a) of this section except within the boundaries of the Mazama Planning Area as described in subsection C of this section. The health officer and DSHS shall develop guidelines to be applied when such reductions are considered by July 1, 1984. Until guidelines have been developed, the health officer may permit such reductions only when an alternative system will be used. The alternative system shall provide a degree of treatment to the sewage before the sewage enters the original, undisturbed soil, equal to or greater than the treatment provided by a mound or sand filter. Mounds and sand filters are defined and the design criteria specified in the appropriate technical review committee guidelines. Until the guidelines have been developed, the resulting gross land area per unit volume of sewage or single-family residence shall not be less than one-half acre.

3. The health officer may reduce the land area requirements found in this section except for land found within the boundaries of the Mazama Planning Area described in subsection C of this section, if the proposed on-site sewage systems are to be located within the boundaries of a recognized sewer utility and where the assessment role has been finalized.

C. Minimum gross land area requirements for any development within the planning area established in the Mazama Comprehensive Sewer Plan – Early Winters Update, amended by the county board of commissioners in Resolution 31-83 and described as “All privately owned lands lying northeast of a line beginning at the southwest corner of the east quarter of Section 9, Township 35N, Range 30 EWM; thence east to the southwest corner of Section 10, Township 35N, Range 29 EWM” shall be determined for each single-family residence or each unit volume of sewage (360 gallons per day) by one of the following methods:

1. Minimum land area requirements for lots created subsequent to the adoption of Resolution 31-83 shall vary with the degree of treatment provided to the effluent prior to final on-site disposal as shown below:

Degree of Treatment

Minimum Land Area Requirement

Septic tank followed by

conventional drainfield or


System not acceptable

Septic tank followed by

drain field bedded in two

feet of medium sand

(nonpressurized distribution)

3 acres

Septic tank followed by

pressurized sandfilter,

pressurized distribution over drainfield bedded with two feet

of medium sand, or mound

2 acres

2. Lots proposed subsequent to the adoption of Resolution 31-83 with land areas of less than two acres shall be evaluated on a case-by-case basis by the health officer for approval. The lot owners shall be required to meet effluent per area equivalency to the recommended lot sizes. Using the total nitrogen as an indicator pollutant, assuming a standard septic tank total nitrogen concentrate of 30 mg. per liter. This approach results in a 0.03 pound per acre per day loading rate for a one acre lot; a 0.015 pound per acre per day loading rate for a one-half acre lot, etc.

3. Lots existing prior to the time of adoption of Resolution 31-83 that cannot meet the minimum land area requirements of subsection (C)(1) of this section shall be handled on a case-by-case basis taking into account new on-site treatment technologies, lot size, development density, soil characteristics, depth to groundwater, and water supply source, and shall at a minimum install a septic tank followed by a pressurized sand filter, pressurized distribution over a drainfield bedded with two feet of medium sand or a mound. (Ord. 85-1 § 8(C), 1985).

13.08.180 Location and setbacks.

A. The minimum distances for location of the various component parts of on-site sewage system are measured horizontally and shall comply with the following table:

Minimum Horizontal Separations


Distance in Feet from System Component

Items Requiring Setback

From edge of SSAS and
replacement area

From septic tank and
distribution box

From building sewer,
collection, and nonperforated
distribution line

Well or suction line1




Water supply line under pressure




Surface waterl, 3




Building foundation



Property lines or lines of easement



Interceptor/curtain drains/drainage ditches




-    upslope from system component


-    downslope from system component



Cuts or banks




-    minimum of five feet or original, undisturbed soil above restrictive layer or layer due to a structural or textural change


-    less than five feet of original, undisturbed soil above restrictive layer or layer due to a structural or textural change and that layer is intersected


1With soil Type I and on other sites where conditions indicate a greater potential for ground or surface water contamination or pollution, the distance from any water supply or surface water may be increased by the health officer.

2A reduced separation can be allowed by the health officer if it can be demonstrated that the reduction will not have an adverse effect. However, in no case shall the separation be less than 75 feet.

3Setbacks from surface waters shall be measured from the ordinary high watermark.

B. The SSAS shall not be permitted in areas where a vertical separation of 48 inches between the high seasonal water table or impermeable layer and the bottom of the SSAS cannot be maintained. Separation requirements when alternative systems are utilized shall follow the recommendations found in the appropriate guidelines by the technical review committee. The health officer shall require such greater vertical separation as needed to protect health when the aquifer is used for a potable water supply.

C. On-site sewage systems shall not be located on slopes in excess of 45 percent (24 degrees). The following table notes the required depths of original, undisturbed soil above a restrictive layer for the various ranges of slope.

Table for Required Soil Depths for Slopes

Range of slopes in percent (degrees)

Required depth of original undisturbed soil above restrictive layer in inches

0 – 30 (0 – 17)

Sufficient to satisfy minimum vertical separation

30 – 45 (17 – 24)*


*The SSAS shall be sized using a maximum loading rate of 0.5 gallons/day/square foot of trench or bed-bottom area.

D. An area where the soil and site conditions are acceptable for the installation of a SSAS shall be maintained for the purpose of system replacement. Except where otherwise authorized by the health officer, it shall consist of 100 percent of the normally needed area.

E. The site of the initial and replacement SSAS shall be selected and maintained so that it is free from encroachment by buildings and other structures. The area shall not be covered by any impervious material and not be subject to vehicular traffic or other activity which would adversely affect the soil.

F. Provisions shall be made to prevent flow or accumulation of surface water over the area where the on-site sewage system is located.

G. On-site sewage systems shall not be located on land forms which are unstable. (Ord. 85-1 § 8(D), 1985).

13.08.190 Construction.

A. The detailed design and construction of all on-site sewage disposal systems shall conform to the “Design Manual: On-site Wastewater Treatment and Disposal Systems,” U.S. Environmental Protection Agency, EPA-625/1-80-012, October, 1980, except where modified by, or in conflict with these regulations.

B. The design for an on-site sewage system shall be performed by or under the supervision of a professional engineer, registered sanitarian, or certified designer. A resident owner, at the discretion of the health officer, may design his or her own system, if a minimum vertical separation of four feet can be maintained.

C. The system shall be designed to receive all sanitary sewage and domestic waste from the building served unless otherwise approved by the health officer. For individual residences, flows of 120 gal./bedroom/day shall be used for design purposes. For other establishments, the typical values noted in the design manual referred to in subsection A of this section shall be used. Any deviations shall be supported by appropriate water usage information and/or the use of low water use fixtures. Drainage from footing or roof drains or any other type of drain shall neither enter the sewage system nor be directed over the area where the on-site sewage system is located.

D. All septic tanks shall be designed in accordance with the “Manual of Septic Tank Practice,” U.S. Public Health Service, DHEW Publication No. (HSM) 72-100 20, 1967, with the following exceptions:

1. All tanks must have a minimum of two compartments with the first compartment consisting of one-half to two-thirds of the required total volume;

2. Inter compartmental apparatus shall be sanitary tees, slots, or baffles assuring that effluent only from the clarified zone passes into the next compartment;

3. Septic tanks to serve single-family residences shall have a minimum liquid capacity based on the number of bedrooms in the residence, as follows:

Number of Bedrooms

in House

Required Minimum Liquid Volume

2 or less






For each add’l bedroom add

250 gallons.

A septic tank designed to serve a facility other than one single-family residence shall have a minimum liquid capacity equal to one and one-half times the projected daily sewage volume, with a minimum of 100 gallons.

4. Concrete tanks shall be approved by the health officer. Tanks made of materials other than concrete shall first be approved by the health officer and DSHS.

5. All septic tanks and pump chambers to be located in high water table areas shall be adequately treated to preclude groundwater intrusion.

6. If the top of the septic tank lies more than 18 inches below the final grade of the ground, well curbing rings shall be set on top of the access ports of the septic tank and brought to within six inches of the ground surface.

E. The following specifications shall be used when constructing an SSAS:

1. Number of laterals: at least two;

2. Length of laterals: not more than 100 feet per lateral;

3. Depth to bottom of trench: 18 to 36 inches;

4. Width of trench: 12 to 36 inches;

5. Slope of tile: not over six inches per 100 feet;

6. Depth of drain rock under pipe: at least six inches;

7. Depth of drain rock over pipe: at least two inches;

8. Depth of backfill over drain rock: at least 12 inches;

9. Center-to-center separation between laterals:

a. Twelve-inch wide trench: 5.5 feet minimum;

b. Twenty-four inch wide trench: 6.6 feet minimum;

c. Thirty-six inch wide trench: 7.5 feet minimum;

d. Drainbeds: 6.0 feet maximum; 3.0 feet minimum.

F. Untreated building paper shall be used to cover the drain rock in SSAS before backfilling; filter fabric, straw, cardboard or five thicknesses of newspaper may be used as a substitute. Filter fabric shall be used to cover the drain rock in alternative systems.

G. Effluent shall be disposed of by means of an SSAS except when approval for other disposal systems is granted by the health officer and/or the department.

1. The size of the SSAS shall be determined from the results of the site review and soil logs per the design manual.

2. The installation and use of cesspools and seepage pits for the disposal of sewage is not permitted.

3. The bottom of an SSAS shall not be deeper than three feet below the finished grade, except under special conditions approved by the health officer. The depth of such a system shall not exceed 10 feet from finished grade.

4. Subsurface absorption beds (see definition of SSAS) may be considered for use only when authorized by the health officer and when the soils are Type 1, 2, or 3.

5. Piping materials shall be approved by the health officer and DSHS. Septic tank inflow and outflow lines must be heavy well construction. (Schedule 3033 or 3034).

6. All on-site sewage disposal systems that require pumping of effluent to drainlines will be required to have pressure distribution to conform with the current technical review committee guidelines.

H. Cover can be used over an SSAS provided that no portion of the SSAS sidewall below the invert of the distribution pipe is installed in this material.

I. Sewage holding tank systems shall not be approved by the health officer. The Board of Health may grant variances for use of holding tanks in certain cases when the following conditions are met:

1. Sewage holding tanks shall be allowed only under controlled part-time, nonresidential usage situations including, but not limited to, recreational vehicle parks, trailer dump stations, and certain limited hour businesses, or on an interim-use basis to handle the emergency situations, or to correct existing problem systems;

2. A management program assuring ongoing operation and maintenance of the holding tank system must be approved by the health officer and in effect.

J. Recreational vehicle pumpout facilities located within the planning area of the Mazama Comprehensive Sewer Plan – Early Winters Update described in subsection C of this section shall be limited to nondischarging types and installed only with the approval of the board of health. (Ord. 85-1 § 8(E), 1985).

Article IV. Inspection

13.08.200 Authority – Approval – Recordation.

The health officer may make inspections during construction to determine compliance with these regulations. No part of any installation shall be covered until approval has been obtained from the health officer. The health officer may waive this requirement provided the installation has been made by a person certified under Article X of this chapter and a designer program has been established according to WAC 248-96-130, provided that the designer performs the final inspection. If deviations from the approved plans and specifications have occurred in construction, a complete set of certified as-built drawings shall be provided to the health officer for a permanent record of the installation. (Ord. 85-1 § 9(A), 1985).

13.08.210 Extra-trip fee.

Additional fees for extra trips will be charged where inspections are requested and the system is not completed. These charges will be based on cost per hour and travel as determined by the current adopted fee schedule. (Ord. 85-1 § 9(B), 1985).

13.08.220 Illegal system installation.

All owners of illegally installed systems will be required to uncover the septic tank access port and the ends of the lateral lines for inspection purposes. (Ord. 85-1 § 9(C), 1985).

13.08.230 Advance notice.

Advance 48-working hours notice will be necessary for the health officer’s final inspection of conventional SSAS systems. (Ord. 85-1 § 9(D), 1985).

13.08.240 Sand filter or mound systems.

Inspections of sand filter or mound systems will be made by the health department as follows:

A. Preconstruction inspection: within five working days;

B. Excavation with 24 inches of medium sand in place: within two working days (48 hours);

C. When the piping is in place, ready for pressure testing: within two working days (48 hours). (Ord. 85-1 § 9(E), 1985).

Article V. Alternative Systems

13.08.250 Establishment of guidelines.

The health officer may issue permits for alternative systems after review and evaluation, provided guidelines for application, design, and construction have been established by the technical review committee. (Ord. 85-1 § 10(A), 1985).

13.08.260 Evaluation of guidelines.

Before a proprietary device or method can be permitted, DSHS must evaluate and accept certification that the device or method satisfies all the criteria of the appropriate technical review committee guidelines. (Ord. 85-1 § 10(B), 1985).

13.08.270 Sand approval.

Sand used in alternative systems shall be approved for use prior to system construction. Sand samples shall be sieved by the Soil Conservation Service, a certified laboratory, or the health officer at a frequency deemed appropriate by the health officer. (Ord. 85-1 § 10(C), 1985).

13.08.280 Pumps and siphons – Conditions.

Pumps and siphons used in alternative systems may be allowed in the second compartment of a two-compartment septic tank when the following conditions are met:

A. Sufficient volume must be available in the second compartment for a dose plus adequate reserve area;

B. The two-compartment tank will at least have a 1,250-gallon capacity for serving a single-family dwelling;

C. The tank must be so constructed that the liquid level in the first compartment will not fluctuate with the pump cycle and liquid level in the second compartment;

D. The center divider between compartments of the two compartment tank must be reinforced and structurally sound;

E. The tank must be coated with a waterproof material in areas with a high seasonal water table. (Ord. 85-1 § 10(D), 1985).

13.08.290 Common point design flows.

All on-site sewage systems with design flows at any common point in excess of 1,000 gallons per day shall utilize pressure distribution. The latest guidelines from the technical review committee shall be used as design and construction criteria. (Ord. 85-1 § 10(E), 1985).

13.08.300 Pressurized distribution systems.

Pressurized distribution systems shall be designed so that laterals, transport lines and manifolds are drained between pumping cycles. Keeping lines filled between cycles is not desirable due to the potential for wintertime freezing. If a drain hole is used to allow septage flow-back to a pump or dosing chamber, the hole must be no larger than one-quarter inch in diameter. (Ord. 85-1 § 10(F), 1985).

13.08.310 Monitoring.

The health officer shall require monitoring of the performance of any alternative system installed for which appropriate guidelines have been established. Monitoring shall be at least on an annual basis. The cost of such monitoring shall be borne by the applicant reimbursed to the health department in accordance with the current fee schedule. (Ord. 85-1 § 10(G), 1985).

13.08.320 Graywater treatment.

When a nonwater-carried sewage disposal system is utilized within the Mazama comprehensive sewer plan planning area described in OCC 13.08.170(C), graywater shall be treated to a degree commensurate with minimum land area as outlined in that section. (Ord. 85-1 § 10(H), 1985).

13.08.330 Pit privies.

Pit privies shall be allowed under certain circumstances with the approval of the health officer, provided:

A. Discharging pit privies shall not be allowed within the Mazama planning area identified in OCC 13.08.170(C);

B. Pit privies shall adhere to the design criteria for pit privies developed by the technical review committee;

C. Pit privies shall adhere to the distance requirements for drainfields described in OCC 13.08.180;

D. Pit privies shall be of fly-tight construction, with self-closing doors. (Ord. 85-1 § 10(I), 1985).

Article VI. Experimental Systems

13.08.340 Approval.

If supportive theory and/or applied research exists, a limited number of specific experimental systems may be permitted. Prior to the installation of such a system, approval shall have been obtained from the local board of health and an experimental system permit shall be obtained from the local health officer. Costs for monitoring and reporting may be included as part of the experimental system permit fee. (Ord. 85-1 § 11(A), 1985).

13.08.350 Use.

The use of an experimental system may be considered when:

A. The experimental system proposed is attempting to correct a failing system and other conventional or alternative systems are not feasible;

B. The experimental system proposed is for new construction where it has been determined that an on-site sewage system meeting the requirements of these rules and regulations could be installed in the event of failure of the experiment. A recorded agreement shall exist stating that, in the event of unsatisfactory performance or a failure to adequately monitor the system and submit the records to the health department, the health officer may direct that use of the experimental system be discontinued and a new system meeting the requirements of these regulations be installed. (Ord. 85-1 § 11(B), 1985).

13.08.360 Guidelines.

General guidelines by the technical review committee for the use of experimental system shall be followed when such guidelines become available. (Ord. 85-1 § 11(C), 1985).

13.08.370 Performance monitoring.

The health officer shall require monitoring of the performance of experimental systems in a manner and with a frequency as established by the technical review committee guidelines. (Ord. 85-1 § 11 (D), 1985).

Article VII. Larger On-Site Systems

13.08.380 Review and approval.

Larger on-site systems shall be reviewed and approved by DSHS prior to any construction. (Ord. 85-1 § 12, 1985).

Article VIII. Installer Requirements

13.08.390 Installation by certified installer required.

All systems and any excavation work associated with installation, alteration or repair of a septic system shall be installed by a certified installer. (Ord. 85-1 § 13(A), 1985).

13.08.400 Certification requirements.

Requirements for certification are as follows:

A. Successful completion of an examination, demonstrating to the health officer knowledge of proper installation practices and awareness of pertinent regulations;

B. Presentation to the health officer a copy of a general contractor’s license and bond or a surety bond in the amount of $2,000 for conventional SSAS installations or $4,000 for alternative system installations. (Ord. 85-1 § 13(B), 1985).

13.08.410 Resident owner doing work.

Nothing contained herein shall prohibit resident owners from installing an individual on-site sewage system or making repairs or alterations on his or her own premises as long as all other requirements of these regulations are satisfied. The resident owner may not contract or hire a person or concern to perform that work, unless that person is a certified installer as set forth in this article. (Ord. 85-1 § 13(C), 1985).

Article IX. Pumper Requirements

13.08.420 Permit required.

It is unlawful for any person, firm, or corporation to engage in the business of cleaning any septic tank, seepage pit, or chemical toilet, or removing other accumulations of sewage without first having obtained a septic tank pumper’s permit from the health officer. (Ord. 85-1 § 14(A), 1985).

13.08.430 Permit and renewal – Application.

The original permit and each renewal shall require a completed application on a form furnished by the health officer and payment of the prescribed fee. (Ord. 85-1 § 14(B), 1985).

13.08.440 Pump tank requirements.

Pumping equipment must be presented to the health officer for inspection and meet the following requirements:

A. The pump tank must be of at least 1,000 gallons in capacity and must be in good repair and of cleanable construction, except, where only the contents of chemical toilets are to be pumped and disposed of, where no water-carried household or commercial sewage is involved, a 1,000-gallon pump truck will not be necessary and the tank need only be of such capacity to hold the contents of the number of chemical toilets being serviced at any given time.

B. All outer contact surfaces and fittings shall be kept in a clean and sanitary condition while stored or in transit; and, all premises served and equipment used shall be left in a clean and sanitary condition.

C. All discharge valves shall be in good repair, free from leaks and fitted with watertight caps.

D. The name of the operating firm shall be prominently displayed on the sides of any pump tank vehicle. (Ord. 85-1 § 14(C), 1985).

13.08.450 Waste removal and disposal.

Septic tank waste shall only be removed by pumpers licensed by the health officer and disposed of in sanitary landfills or other areas approved of by the health officer in a manner approved by the health officer. (Ord. 85-1 § 14(D), 1985).

Article X. Alternative System
Designer Program

13.08.460 Designer’s license.

It is unlawful for any person other than the health officer to engage in the functions of being a sewage system designer without a sewage system designer’s license. Applications for a sewage system designer’s license shall be made to the health officer on forms provided by the health officer. Such license applications may be denied if the applicant is found to be unqualified, after examination as hereinafter provided, to perform the necessary functions of a licensed sewage system designer in conformity with WAC 248-96-130 or with other rules and regulations promulgated by the health department or DSHS. (Ord. 85-1 § 15(A), 1985).

13.08.470 Examination.

Prior to the issuance of a license to persons other than licensed engineers and/or registered sanitarians, the health department shall require written examination of the applicant’s knowledge of sanitary system principles and the rules, regulations, laws and ordinances affecting the public health and safety with respect to disposal systems. (Ord. 85-1 § 15(B), 1985).

13.08.480 License fee.

The initial license fee shall be in accordance with the adopted fee schedule. No fee will be charged for licensed engineers or registered sanitarians. At the end of each calendar year all licenses shall become null and void. Licenses may be renewed for a fee established by the adopted fee schedule, but such renewal must be applied for prior to January 15th of the year for which the renewal is sought. No fee shall be refundable in full or in part. A sewage designer’s license shall not be transferable. (Ord. 85-1 § 15(C), 1985).

13.08.490 Surety bond.

Prior to the issuance of a sewage system designer’s license, the applicant must provide a surety bond approved as to form by the county prosecutor attorney in the sum of $4,000 directed to the health officer, and for the use and benefit of all persons who may be injured or aggrieved by the wrongful act of such sewage designer, executed by a surety company authorized to do business in the state of Washington. The bond shall be conditioned that the holder of the state of Washington sewage system designer’s license is performing work governed by these rules and regulations and shall exercise all reasonable care and skill and shall comply with all the terms and conditions of these and all other applicable rules and regulations. The bond must be kept in effect during the period of time for which the sewage system designer’s license is issued and cancellation or termination of the bond shall automatically and without notice suspend the sewage system designer’s license.

The surety bond shall remain in force for one year following cancellation of and/or termination of sewage system designer’s license. (Ord. 85-1 § 15(D), 1985).

13.08.500 Suspension of designer’s license.

A sewage system designer’s license may be suspended temporarily for a period not to exceed 60 days by the health officer with concurrence of the board of health for incompetency, or negligence, or misrepresentation in giving false information, or failure of the holder to comply with the requirements of these regulations or any other applicable regulations. In the event of suspension, no rebate shall be forthcoming for any unexpired portion of the license period. (Ord. 85-1 § 15(E), 1985).

13.08.510 Revocation of sewage system designer’s license.

A. For serious or repeated violations of any of the requirements of the regulations set out in this chapter, the sewage system designer’s license may be permanently revoked by the health officer with the concurrence of the board of health after an opportunity for a hearing has been provided by the health officer. Prior to such action, the health officer shall notify the sewage designer in writing, stating the reasons for which the sewage system designer’s license is subject to revocation and advising that the sewage system designer’s license shall be permanently revoked at the end of 10 days following service of such notice, unless a written request for hearing is filed with the health officer by the holder of the sewage system designer’s license within such ten-day period. A sewage system designer’s license may be suspended for cause pending its revocation or a hearing relative thereto. If, after revocation of a sewage system designer’s license the applicant desires to reapply for a license, the applicant must wait six months prior to reapplication and taking the examination. In the event of revocation, no rebate shall be forthcoming for any unexpired portion of the license period.

B. If the health officer suspends or revokes a sewage system designer’s license, that sewage system designer shall not proceed with any further functions of a sewage system designer. (Ord. 85-1 § 14(F), 1985).

Article XI. Appeals

13.08.520 Appeal of health officer decision.

Decisions of the health officer may be appealed to the board of health. The board of health consists of the county commissioners and the health officer. Appeals must be made in writing to the health officer within 10 working days of the decision which is being disputed. A hearing date with the county board of health will be scheduled after receipt of the appeal. Any variations from this chapter which are in conflict with Chapter 248-96 WAC must have concurrence from DSHS. (Ord. 85-1 § 16, 1985).

Article XII. Waiver

13.08.530 Waiver.

The board of health may waive this chapter or portion thereof, provided that the waiver is consistent with the intent of this chapter that no public health hazard will result and the waiver will not violate the requirements of Chapter 248-96 WAC. Any waiver which will violate the requirements of Chapter 248-96 WAC must have the concurrence of DSHS. (Ord. 85-1 § 17, 1985).

Article XIII. Compliance

13.08.540 Human occupancy.

It is unlawful to dwell in, own, or rent a dwelling unit, commercial structure, recreational development, or other structure commonly used by human beings without one of the following systems in proper working order:

A. A sewage disposal system approved through this chapter;

B. A municipal sewerage system;

C. A sewage disposal system approved through earlier ordinances or resolutions of the county;

D. A sewage disposal system installed prior to the enactment of any county ordinance or resolution governing the same. (Ord. 85-1 § 18(A), 1985).

13.08.550 No surface discharge.

Sewage from any on-site sewage system, including septic tank waste, shall not be discharged to surface water or upon the surface of the ground. (Ord. 85-1 § 18(B), 1985).

13.08.560 Malfunctioning system – Vacation of premises.

It is unlawful to use or maintain a malfunctioning sewage disposal system. Upon the health officer’s discovery of the existence of such a system, written notice of violation shall be given to the recorded owner and/or occupant of the premises. Upon failure to adequately repair and restore the sewage disposal system to proper working order within 30 days of the giving of notice, the premises shall be vacated, and failure to so vacate, shall constitute an additional violation. (Ord. 85-1 § 18(C), 1985).

13.08.570 Violation – Abatement.

All violations of this chapter are determined and declared to be detrimental to the public health, safety and welfare, and public nuisances. All conditions which render any building, structure, premises, land use or portion thereof to be used or maintained in violation of this chapter shall be abated if provisions for their continuance made pursuant to this chapter are not satisfied. (Ord. 85-1 § 18(D), 1985).

13.08.580 Injunction.

The prosecuting attorney may commence an action to restrain and enjoin acts in violation of this chapter. (Ord. 85-1 § 18(E), 1985).

13.08.590 Condemnation.

The health officer may condemn, according to law, any residence or other establishment which is accumulating or disposing of sewage in a manner contrary to the requirements of this chapter. (Ord. 85-1 § 18(F), 1985).

13.08.600 Violation – Penalty.

Violation of any of the provisions of this chapter constitutes a misdemeanor and shall be punishable by a fine of not more than $500.00 or imprisonment. For the purpose of this chapter each section violated shall constitute a separate and distinct offense, and each day’s violation shall constitute a separate and distinct offense, and shall be punishable as such. (Ord. 85-1 § 18(G), 1985).